Metallic composition



Patented July 20, 1926.

UNITED STATES PATENT orsics.

' JOHN R. TOWNSEND, OF BROOKLYN, NEW YORK, ASSIGNOR T WESTERN ELECTRIC COMPANY, INCORPORATED, 013 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METALLIC COMEOSI'IION.

R0 Ilrawlng.

This invention relates to contact metals, and its object is an alloy for electrical contacts which combines resiliency with durability and which will reduce to a minimum a the possibility of arcing upon the approach or separation of the contacts.

Ordinary wiping contacts are very subject to wear, and acoordin 1y tend to become abraded. In this condition the tendency for an electrical arc to form just previous to .and directly after contact is made is" fireatly increased. This arcing is not only eleterious in itself, but it tends to erode the contacts still further, making them more 1!! subject to wear and to arcing. The deterioration of contacts under such conditions is therefore rapid.

This invention rovides contact members .which are abrad but little when wiping contact is made therebetween, and by their use the ordinary wear andarcing of the contact members and their subsequent rapid deterioration is avoided. To this end the contact memberslare formed of a phosphorbronze to which a small portion 'of lead has been added; for example, a metallic composition containing the following ingredients;

tin 4 to 5 lead 1 to 4%, phosphorus .05 to 25%, copper remainder. $0

siliency for use in spring contacts and is Such a composition has the necessary re- Application filed May 26, 1923. I Serial No. 841,747.

also suificiently resistant to the efiects of wear to provide wiping contact members which will be subject to arcin and deterioration in an unusually small degree. Wip- Ell ing springs made of this material, for instance, show little effects of wear even after five million wiping make and break operations, whereas bronze wiping springs are useless after three mllhon operations. Con- 49 of a phosphor bronze alloy containing an I amount of lead in slight excess of its solubility and at least as small as 4%.

3. A resilient contact member composed of a metallic composition containing the following metals insubstantially the follow- Ill ing proportions: tin 4 to 5 lead 1 to 4%, phosphorus .05 to 25%, and copper,

remainder.

- In witness whereof, I hereunto subscribe my name this can day of May A. 1)., 1923.

JOHN R. TOWNSEND. 

